This invention relates to apparatus for readily exchanging a hot runner utilized in a vertical type injection molding machine.
One example of a prior art hot runner utilized in a vertical type injection molding machine is disclosed in Japanese Patent Publication No. 10287/1986 and No. 49621/1990. Inventions described in these Patent Publications relate to absorption of thermal expansion, correction of nozzle position, leakage of resin, prevention of dangerous state resulting from generation of thermal stress and prevention of leakage of the resin from an opening and closing valve at the nozzle portion on the side of the hot runner. These inventions relate to a vertical type injection molding machine which manufactures only certain types of products.
In recent years, user needs have become varied. In the field of large size molded plastic products higher production efficiency has been demanded so it has been necessary to satisfy demand by producing a small number of products of various kinds. As a consequence, in a vertical type injection molding machine utilizing a hot runner it is necessary to quickly change colors and resins. However, in conventional machines, it was not necessary to instantly remove an old resin remaining in the hot runner. Further, due to the construction of the hot runner it is extremely difficult to instantly remove the old resin remaining in the hot runner. Furthermore, the construction of mounting and assembling the hot runner becomes complicated, with the result that according to the prior art, the hot runner was not contemplated to be frequently removed.